# Principles & requirements Project Developers shall demonstrate that they comply with all principles and requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md), and described below with a specific focus on distributed biochar production. {% content-ref url="/pages/CRADNrj4mfS258PN3x7N" %} [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules.md) {% endcontent-ref %} ## Additionality {% tabs %} {% tab title="Regulatory surplus analysis" %} **Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities (for removal and avoidance activities). It is acceptable if regulations promote or set targets for these activities, because the resulting increase in activities shall be accounted for in the [baseline scenario](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope.md#baseline-scope). At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Science Team. Project Developers are only required to provide a country-level regulatory surplus analysis. {% endtab %} {% tab title="Investment analysis" %} **Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option. The investment may cover: * The creation and launching of new sites * Expansion of capacity of existing activities * Expansion by installing new processes Business plans shall be provided as initial proof for investment analysis. During verification, **audited financial statements** **must be provided as proof** that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment. Note that for investments in expansion, **only the additional carbon removals enabled by the expansion shall be eligible for Rainbow Carbon Credits.** {% endtab %} {% tab title="Barrier analysis" %} **Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to: * Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets in the business plans and loan documents, and that carbon finance would make it financially viable. * Institutional barrier: description of new regulation that the project must make costly changes to comply with, financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable. For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers. {% endtab %} {% endtabs %} ## Durability #### Durability threshold All projects certified under this methodology shall prove **durable carbon removals for at least 100 years**. Project Developers may claim an extended durability threshold of 1000 years if they choose the 1000-year pathway for [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification.md#biochar-carbon-storage) and measurements. #### Reversal risk assessment The major carbon reversal risks from biochar carbon storage are: 1. **Insufficient biochar stability**, where biochar carbon is not sufficiently carbonized and is decomposed by microbes and soil organisms, resulting in re-emission of CO2. 2. **Failure to durably incorporate into a permanent matrix** (e.g. soil or soil-like material), where biochar is instead burned or destroyed, intentionally or unintentionally (e.g. as fuel, in storage fires, or via waste incineration). This methodology establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections: * measuring the durable carbon fraction * verification of biochar end use Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered **negligible** for biochar application to soils. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals. All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md#durability). #### Risk mitigation: Measuring permanent carbon fraction Not all biomass carbon that is converted to biochar is expected to remain durably stored. The durability of biochar carbon depends on the its physicochemical stability, which is influenced by factors such as carbonization temperature and biomass feedstock. Project Developers shall measure one of the following well-known [proxy indicators](#user-content-fn-1)[^1] of biochar durability for each [Production Batch](#user-content-fn-2)[^2]. These indicators serve both as **eligibility thresholds**, and as inputs to **quantify the permanent fraction of carbon** ($$F\_{perm}$$) expected to remain durably stored beyond the applicable durability threshold. The fraction of permanently stored carbon shall be quantified using the models and equations specified in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification.md#biochar-carbon-storage) section. Only this fraction shall be issued as removal RCCs.
PathwayIndicatorThreshold requirement
100-year pathwayHydrogen-to-organic-carbon atomic ratio (H/C_{\text{org}})H/C_{\text{org}} must be less than 0.7
1000-year pathwayRandom reflectance distribution
  • The fraction of the biochar residual organic carbon that has a random reflectance of 2% or higher can be considered inertinite, which is an extremely stable, permanent storage of mineral-like organic carbon.
  • Must also have H/C_{\text{org}} less than 0.7
The distinction between the 100-year and 1,000-year durability pathways provides supplementary qualitative information and does not affect the inherent attributes of the removal RCC. These indicators are **suitable proof that a substantial fraction** of the carbon present in biochar is permanently stable. The **specific amount** of permanently stored carbon is determined using the models and equations detailed in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification.md#biochar-carbon-storage) section. These durability indicators shall be monitored for each Production Batch according to this methodology's [Sampling Requirements](#sampling-and-measurements). Issuing removal RCCs only for the verified, highly stable fraction of biochar carbon mitigates the risk of biological decomposition and re-emission after soil application. #### Risk mitigation: Proof of biochar end use Project Developers shall prove that all biochar has been used in the intended durable storage application and [eligible biochar end use](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope.md#eligible-biochar-product-and-end-use) (e.g. incorporated into soils, added to fertilizer mixes, mixed in concrete). This shall be done by documenting all of the following information in dMRV: * Proof of **delivery and use** of the biochar to its point of end use, specifying the date, GPS coordinates, address, amount of biochar, name of the user/buyer, and Production Batch ID. * **Photo diary of biochar application and/or mixing**, including time-stamped and geo-located photos of the process. ## No double counting Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry.md), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules.md), including not double using or double issuing carbon credits. Project Developers shall demonstrate that they hold the sole right to issue carbon credits for all biochar produced under the project, and that no third party will seek to issue credits for the same biochar. * If biochar is applied to soils by participants within the project network (e.g., farmers who also provide biomass or operate kilns), this is considered to remain within the project scope through to end use, and no additional double counting documentation is required. * If biochar is transferred to third parties, such as farmers outside the project network or companies incorporating it into construction materials, then Project Developers shall obtain recognition that the Project Developer holds the sole right to issue credits for that biochar, and that the recipient will not seek to issue credits for its use. ## Co-benefits Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be quantified, monitored, and audited for each verification and credit issuance. Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here. SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits. *Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*
UN SDGExampleProof
SDG 1.5: Build the resilience of the poor and those in vulnerable situations, ensure significant mobilization of resources from a variety of sourcesKiln Operators, who are often smallholder farmers, receive direct payments from carbon finance generated (mandatory, see Benefit sharing requirements).Payment slips, bank transaction records, contracts.
SDG 2.4: Ensure sustainable food production systems, increase productivity, help maintain resilient ecosystems, improve land and soil quality.Biochar application to agricultural soils can increase crop yields.Proof of biochar sales to farmers for agricultural use, invoices, receipts of sale of biochar to farmers.
SDG 3.9: reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contaminationAgricultural residues (feedstock) are pyrolyzed instead of open-field burning, improving air quality.Biomass type records, local data on traditional burning practices.
SDG 12.2: Sustainable management and efficient use of natural resourcesBiomass waste is converted into valuable biochar instead of being burned or discarded.Biomass type records, local statistics on traditional biomass disposal methods.
## Environmental and social safeguards Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.** Projects must follow all national, local, and European (if located in Europe) environmental regulations related to, for example, pyrolysis, gasification, waste feedstock management, and biochar spreading on soils. ### Biomass requirements #### Waste status Project Developers shall **provide proof of waste status** for any biomass feedstock categorized as waste. This can be done via any one of the following three methods: * **Price**: if Project Developers did not pay for the biomass, or if they were paid to handle it, the biomass can be considered waste. Acceptable proof includes invoices, receipts, or contracts. * **Contextual analysis**: Project Developers may submit an analysis supported by reputable sources that the biomass 1) could not be used as main material products, and 2) was not grown for the purpose of CDR[^5]. * **Positive list of wastes**: if the biomass is included in the following list, it can be considered waste. Acceptable proof includes invoices, receipts, contracts, or photographic evidence and is required for validation: {% columns %} {% column %} * sawmill residues * shavings * bark * forestry tops and branches * wildfire management residues * sugar beet pulp {% endcolumn %} {% column %} * straw * corn cobs * wood from horticulture (trimmings or whole plants) * nut shells * bagasse {% endcolumn %} {% endcolumns %} #### Invasive species status Project Developers shall **provide proof of invasive species status** for any biomass feedstock categorized as invasive species. This may include but is not limited to peer-reviewed scientific literature documenting the species as invasive in the specific region, national or regional government invasive species lists or registers, regional intergovernmental lists (e.g. IUCN Invasive Species Specialist Group database), or local official weed management orders. Project Developers shall provide an **Ecosystem Restoration Plan**, outlining all of the following: * the extent of invasive species harvesting, and how much biomass is left in the field after harvesting * procedures to ensure only targeted invasive species are harvested * impacts on biodiversity and habitat loss * impacts on ecosystem carbon loss #### Forestry certification Biomass feedstock originating from forests shall provide at least one of the following forestry sustainability certificates (or similar, with a sufficient justification): * FSC (Forest Stewardship Council)⁠ * PEFC (Program for the Endorsement of Forest Certification)⁠ * RSB (Roundtable on Sustainable Biomaterials)⁠ * SFI (Sustainable Forestry Initiative)⁠ * SBP (Sustainable Biomass Program)⁠ These certifications are used to prove: * Legal and transparent chain of custody * Proper forest regeneration * Safeguarding biodiversity and soil health * Historically stable or increasing forest carbon stocks * Sound socio-environmental practices in forestry operations⁠ #### Biomass stakeholder consultation In addition to the general Rainbow [stakeholder consultation](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md#stakeholder-consultation) requirements, Project Developers shall **explicitly consult stakeholders on the project's use of biomass.** This shall cover the Project Developer's right to use the biomass, the biomass status as waste or invasive species, and the alternative fate of the biomass. ### Kiln operation requirements Distributed biochar production may pose health and safety risks to Kiln Operators, including but not limited to risk of burns and inhalation of smoke and pollutants. Project Developers shall prove all of the following: * Kiln Operators and Supervisors follow required [safety training](#trainings) * Kiln Operators are equipped with and use burn protection equipment such as fire resistant gloves or appropriate footwear * Kiln Operators are equipped with and use smoke protection equipment such as eyewear and masks * pyrolysis occurs in ventilated outdoor spaces ### Biochar requirements Biochar applied to soils must be below the pollutant concentration thresholds outlined in Table 2, defined by the [World Biochar Certificate Guidelines](#user-content-fn-6)[^6] (for WBC-Agro). This shall be measured on a representative composite sample of biochar **anytime biomass feedstock changes, or annually**, if biomass feedstock does not change. *Table 2 The thresholds for pollutant concentrations allowed in biochar, as detailed in the* [*World Biochar Certificate Guidelines*](#user-content-fn-6)[^6]*.*
SubstanceLimit amount (g/tonne dry matter)
Pb300
Cd5
Cu200
Ni100
Hg2
Zn1000
Cr200
As20
8 EFSA PAH1
{% hint style="info" %} *Disclaimer: The European Biochar Certificate (EBC) and the World Biochar Certificate (WBC) are independent certification programs designed to ensure the quality of biochar products. These certifications are administered and trademarked by Carbon Standards International (CSI) and are distinct from the Rainbow certification and the issuance of carbon credits.* *The threshold values provided here are based on the voluntary guidelines of the World Biochar Certificate (WBC), reproduced with permission. While these values have been adopted by the Rainbow standard as pollutant thresholds, they are only indicative. Meeting these thresholds for Rainbow certification does not imply eligibility for or any association with the EBC or WBC programs. Project Developers certified under the Rainbow standard shall not make claims or use any trademarked materials from CSI, unless explicitly allowed by CSI.* *Voluntary certification under the WBC and EBC schemes is overseen by CSI and includes additional requirements beyond pollutant thresholds.* {% endhint %} ### Environmental and social risk assessment Project Developers shall fill in the [Rainbow Distributed biochar risk assessment](https://github.com/riverse-carbon/standard-documentation/blob/main/methodologies/distributed-closed-kiln-biochar/risk-evaluation-template.md), to evaluate the identified environmental and social risks of projects. The identified risks include: * Heavy metal or other pollutants in biochar applied to agricultural soils * Disruption of soil health when collecting and exporting organic matter * Presence of heavy metals, toxins or other chemical pollutants in the biomass⁠ * Spread of diseases or invasive species * Cultivation of feedstock * Deforestation from use of forestry products as feedstock * Distant transport of feedstock inputs (>100 km) * Timely and fair payments to smallholder farmers * Safe kiln operation and training events to prevents burns * Use of large amounts of water, if water is scarce, for quenching Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores. Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms. Additional proof may be required for certain high risk environmental and social problems. The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project. {% hint style="info" %} Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template. {% endhint %} {% hint style="info" %} All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules. {% endhint %} Project Developers shall follow the requirements in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md#environmental-and-social-safeguards) for conducting stakeholder consultation, and where [IPLCs ](#user-content-fn-7)[^7]are involved, obtaining free prior and informed consent (FPIC). Although the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements.md#environmental-and-social-safeguards) requires benefit sharing only if IPLCs are involved, this methodology requires it in all cases, as detailed in the following section. #### Benefit sharing Project Developers shall demonstrate that Kiln Operators are fairly compensated for their contribution to the project. This includes **timely payments** that are not deferred until credits are issued and sold, and **allocation of a fair share** of carbon finance revenues. The committed timing and amount of benefit sharing shall be defined by Project Developers and **disclosed transparently in project documentation** on the Rainbow registry. Project Developers shall demonstrate adherence to this commitment annually by providing payment slips, bank transaction records, or other ex-post evidence of payments having occurred. ## Leakage Project Developers shall source biomass in a way that reduces leakage. Project Developers shall **assess** and, if identified to be material, **quantify** the leakage caused by the distributed biochar project and **deduct** the associated emissions from the project removals. This shall be done by first identifying the alternative use of biomass, and then assessing the leakage risks from the following identified leakage sources: * Biomass diversion and replacement * Counterfactual biomass carbon storage Where leakage risks are identified, Project Developers shall **mitigate** the risk, and document such efforts to do so. Where leakage cannot be fully mitigated, leakage emissions shall be counted towards the project induced GHG emissions and therefore **deducted from project removals**. #### Alternative use Project Developers shall evaluate the most likely alternative use/s of each type of biomass used, in order to assess leakage risks associated with **the baseline carbon storage and the diversion of biomass**. The assessment shall be transparent and conservative. The alternative use shall address questions such as: * was the biomass used for a product or service, that now needs to be replaced (e.g. bioenergy production)? * was the biomass going to store carbon anyway (in the biomass itself and/or in the soil)? Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting. A short list of likely alternative uses may be provided for descriptive purposes, but for the purpose of further analysis, one single alternative use per biomass shall be proposed. #### Biomass diversion and replacement Using waste biomass helps mitigate activity shifting leakage. However, waste biomass or invasive species may still have valuable alternative uses. If the [Alternative use of biomass](#alternative-use) assessment concludes that the biomass has a **valuable existing use**, Project Developers shall assess the impacts of diverting it for biochar production. This assessment must address, at a minimum: * The availability of **substitute materials** (either the same material, if locally abundant, or alternative materials that fulfill the same function). * The risk of **indirect land use change or deforestation**, particularly if diverting the biomass creates demand for new materials to replace its original function. Specifically, Project Developers shall identify the **most likely replacement product or process** for the diverted biomass. Project Developers shall justify the amount of replacement product needed to replace the original function of the biomass based on the business-as-usual (BAU) function, using an appropriate conversion factor. Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting. #### Counterfactual biomass carbon storage Projects shall only be credited for carbon storage that is genuinely additional. **If the alternative use of biomass was to be left on the soil or reapplied to soils** for nutrient recycling, then any permanent carbon storage that would have occurred anyway in the absence of the project shall be **deducted from the project's carbon removal capacity**. * Any carbon that is demonstrated to remain stored in the feedstock for up to **50 years** shall be considered as baseline carbon storage. * A **minimum of 0.5%** of the feedstock carbon content is assumed to remain stored and deducted from the project removals. [Details](/methodologies/distributed-closed-kiln-biochar/ghg-quantification.md#biomass-leakage) are outlined in the GHG quantification section. #### Upstream and downstream emissions Upstream and downstream emissions are accounted for in the life-cycle based GHG quantifications in companion [modules](/modules/processing-and-energy-use.md). ## Monitoring Monitoring Plans for this module shall include, but are not limited to, tracking of the following information:
Measurement frequencyParameters
Each Production Batch, on a single representative sample of biochar
  • H/C_{\text{org}} and organic carbon content (full description here)
  • Inertinite content (fraction of the distribution sample that has a random reflectance of 2% or higher) and residual carbon (if calculating 1000-year removals) (full description here)
  • Biochar moisture content, on at least 3 biochar samples (if measuring biochar amount via mass) (full description here)
Once per year, or anytime biomass feedstock changes
  • Methane emissions, on three runs representative of all other kilns in the same Production Batch (full description here)
  • Environmental pollutants of biochar, on one composite sample mixing biochar from each kiln run (full description here)
  • Dry bulk density of biochar, on at least one sample from each kiln (i.e. 20 different kilns, 20 bulk density measurements) (if measuring biochar amount via volume) (full description here)
  • Biomass to biochar conversion factor (if not weighing the biomass input of each kiln run) (full description here)
  • Updated biomass leakage assessment (full description here)
Each kiln run
  • Moisture content of biomass input (full description here)
  • Type of biomass input (full description here)
  • Amount of biomass input, via precise mass measurements if using a feedstock mix, or estimates if using a singular biomass (full description here)
  • Amount of any energy inputs used, for example for process ignition.
  • Mass or volume of fresh biochar produced (full description here)
  • Temperature curve measured in each kiln using real-time sensors, proving pyrolysis has occurred (full description here)
  • Sampling records (proof of setting aside a small sub-sample of biochar, to be combined with sub-samples from all other kiln runs in the same Production Batch) (full description here)
All biochar used
  • Proof of eligible, durable biochar end use, with names and GPS coordinates of spreading locations, among other information (full description here)
Once per year
  • Kiln Operator training (full description here)
  • Proof and findings from the visits of Kiln Supervisor to each Kiln Operator (full description here)
  • Proof of calibration and accuracy of onsite scales for weighing biochar to determine biochar amount (full description here)
Once per verification and credit issuance
  • Quality oversight report from the Project Developer (full description here)
  • Environmental sustainability and Leakage compliance of biomass feedstock (full description here and here)
The Project Developer is the party responsible for adhering to the Monitoring Plan. ## dMRV requirements Distributed biochar uniquely heavily relies on third-party [**dMRV**](#user-content-fn-9)[^9] **platforms** to allow for detailed tracking of operations across a network of Kiln Operators. Project Developers shall select the dMRV to be used by Kiln Operators and Supervisors to document the operating procedures. The chosen dMRV shall provide step by step procedures to Kiln Operators and be able to track the following:
Item to trackFurther requirements
Eligible kiln useScanned QR codes of individual kilns and photos of the kiln displaying the required technical features
Biomass moisture contentPhotos of sensor readings
Biomass preparation and amount
  • Photos of the biomass to be pyrolyzed before each kiln run and
  • The mass or volume of biomass used
Pyrolysis temperature and durationContinuous thermocouple readings
Pyrolysis process qualityPhotos taken throughout the pyrolysis process, including at least one after the last addition of biomass to the kiln, showing the intact and clean flame curtain
Rapid quenchingThrough time-stamped photos or short videos showing the start and end time of quenching
Amount of biochar produced
  • Volume of biochar produced from each kiln run, and bulk density measurements conducted by the Kiln Supervisor, or
  • Mass of biochar produced from each kiln run, and moisture content measurements
Biochar sampling recordsScanned QR codes of the original biochar bags from which the sample is taken, and photos of the sample
Biochar delivery and applicationScanned QR codes of biochar bags for delivery and photos
Aggregated measurements and dataFor GHG quantification
The amount of energy inputs used, for example for process ignition, may be tracked or calculated outside of the dMRV platform. Methane emissions testing, including results and photos of the process, may be handled in the dMRV platform or in a separate report shared with Rainbow and the VVB. All photographs must include a timestamp and GPS coordinates. All temperature curves must include a timestamp. Any data tracked directly in the dMRV platform and uploaded with a delay must: * include a timestamp of when the upload occurred, and * be uploaded as a batch with all relevant data upon connectivity, as opposed to manually uploading individual chosen files from chosen kiln runs, to prevent selective submission of preferred data. The dMRV platform must prevent Kiln Operators from modifying data once it has been uploaded. Data from dMRV shall be made available and verifiable by Rainbow, the Project Developer and the VVB, through an oversight-only view, and [exportable files](#user-content-fn-10)[^10]. All project records must be retained for a minimum of five years following the end of the project's final monitoring period. At project validation, Rainbow will review the proposed dMRV platform to ensure it is capable of providing the above-mentioned data and proof. After a dMRV platform design is validated and approved as eligible, the platform will be added to Rainbow’s published list of eligible platform. For any future projects using the same dMRV platform, the platform shall be considered **automatically eligible**. {% hint style="info" %} The use of an approved dMRV platform is not sufficient to ensure project compliance with the present methodology. All listed data points and proof shall be uploaded to the dMRV platform in order to issue credits. If any piece of operational proof or documentation is missing in dMRV, the entire kiln run is ineligible. {% endhint %}
RoleUse of dMRV platform
Kiln Operators
  • Directly upload the required information to the dMRV platform, and flag any known anomalies.
Kiln Supervisors
  • Directly upload any biochar bulk density and/or moisture content measurements to the dMRV platform (depending on the measurement method for the amount of biochar produced), and flag any known anomalies.
Project Developer
  • Check the information and proof for every kiln run recorded on the dMRV platform, ensuring its accuracy and data preparation (unless outsourcing this task to the dMRV provider, see the Raw data checking section)
  • Provide a report on oversight findings, listing non-conformities, adjusted data, and kiln runs excluded from certification.
VVB
  • Check the complete raw records in dMRV of a random sample of kiln runs, to cover at least 20% of all events.
  • Check all records related to biochar bulk density and/or moisture content measurements conducted by Kiln Supervisors, as detailed in the biochar amount produced section.
  • Findings shall follow the non-conformity procedure outlined in the Rainbow Procedures Manual. Major non-conformities shall trigger a more thorough audit of a larger sample of events.
## Quality and oversight ### Raw data checking The Project Developer is ultimately responsible for the quality and accuracy of raw records submitted to the VVBs for audit, and identifying and flagging runs that do not meet the quality threshold. All **records from each kiln run shall be individually checked**, ensuring at a minimum all of the following components: * the duration of the kiln run is consistent with the amount of biochar produced * the amount of biomass feedstock used is broadly consistent with the amount of biochar produced, based on photographic evidence of the feedstock pile prior to the run * the amount of biochar produced is [broadly consistent](#user-content-fn-11)[^11] with the amount of biochar reported as applied in an eligible end use * pyrolysis temperature is consistently high throughout the duration of the kiln run. Project Developers shall suggest their own definition for acceptable temperature curves upon validation. Full details are in the [temperature curve](#temperature-curves) section * quenching was rapid enough to mitigate methane emissions Any kiln run with incomplete data, or that demonstrates unsatisfactory practices, is rendered ineligible for crediting (except for the tolerance threshold of [temperature curve](#temperature-curves) failures). Raw data checking may be completed by the Project Developer, or may be delegated to the Rainbow-approved dMRV provider. Data checking may be completed manually, or via a dMRV-enabled system for automatically scanning for and flagging anomalies. Criteria and anomalies shall be either defined at the dMRV level and applied across all projects, or according to project-specific criteria, and shall be approved by Rainbow. If opting for an automatic flagging approach, the dMRV provider must demonstrate via trial runs that it is capable of flagging deviations from the criteria, and define a protocol for random manual checks. The VVB shall also manually review the complete raw dMRV records for a random sample of kiln runs, covering at least 20% of all events. ### Kiln Supervisor site visits The Kiln Supervisor shall **visit each Kiln Operator annually and observe one kiln run**, ensuring: * feedstock is properly added to the kiln * biomass moisture content measurements are taken appropriately * storage conditions for biomass and biochar are appropriate * biochar sampling procedures are followed The Kiln Supervisor shall also collect the **Site Composite Sample** during this site visit, which is mixed with other Site Composite Samples to generate the **Production Batch Representative Sample**. Biochar durability indicators and bulk density measurements (if using the biochar volume approach) are done on this biochar sample. See the [Biochar sampling procedure](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements.md#biochar-sampling-procedure) section for more details. Proof of the site visits shall be included in the Monitoring Plan and submitted at least once per year, including the name of the Kiln Supervisor, date of visit, and the findings and follow up actions of each Kiln Operator. {% hint style="info" %} Note that the Kiln Supervisor site visits are in addition to the annual VVB site audits, described in the [Certification Requirements](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope.md#certification-requirements) section. {% endhint %} ### Quality oversight report Project Developers shall prepare a report, **upon each verification and credit issuance**, summarizing the findings of dMRV oversight via raw data checking and site visits, as described above. This report shall detail: * the cumulative biomass used, biochar produced, and biochar applied in an eligible end use, noting any discrepancies and justification, * any kiln runs that were excluded from certification and the reason for exclusion * any non-conformities in data uploaded to dMRV and their remediation * any non-conformities or failure to adhere to best practices in onsite visits, and their remediation ### Temperature curves All kilns shall be equipped with fixed, continuously-logging thermocouples, producing a documented temperature curve over time for each kiln run. The purpose is twofold: to ensure pyrolysis actually occurred, and to assess the quality of the pyrolysis run. To **ensure pyrolysis actually occurred**, the temperature curve must show that the temperature of the pyrolysis zone remained above 350°C for the entire process, excluding the ramp up and quenching phases. To **assess pyrolysis quality**, Project Developers shall submit project-specific criteria for evaluating temperature curves during project validation. These criteria shall be used to flag and exclude ineligible kiln runs, and shall be approved by Rainbow and the VVB. Criteria shall be designed to flag: * Incomplete biomass drying prior to pyrolysis, and * Improper feedstock loading rates, such as overloading events that cause a drop in pyrolysis temperature or extinguish the flame curtain. Criteria definitions shall address target temperatures, durations, and allowable variance, and ramp-up period, quenching, and main pyrolysis time. **Placement**: Thermocouples should be placed inside the kiln at an appropriate number and spacing to meet the above-mentioned performance requirements. For kilns where it is not technically feasible to place thermocouples inside, they may be placed on the outside of kilns and heat-transfer or energy-balance models shall be used to demonstrate that pyrolysis zone remained above 350°C for the entire process. **Checking temperature curves**: Temperature curve results from all kiln runs shall be individually checked, according to the [Raw data checking](#raw-data-checking-closed-kiln) requirements. **Tolerance for thermocouple failures**: some kiln runs are expected to experience thermocouple failures. Biochar from kiln runs that experience a thermocouple failure may still be credited if all other required proof is still available for the kiln run, if the reason for the failure can be explained and justified, and if a kiln does not experience consecutive failures. This is applicable to kiln runs that make up a cumulative maximum of 5% of the biochar in the [Production Batch](#user-content-fn-2)[^2]. Beyond this 5%, any kiln runs with thermocouple failures shall be discarded and not credited. The biochar in such excluded kiln runs does not count towards the size-limit of the Production Batch. **Calibration**: All thermocouples shall undergo regular calibration. {% hint style="info" %} **Integrated temperature sensors** are a promising and relatively new pathway to **verify pyrolysis quality and consistency** for certification of distributed biochar production, ensuring low methane emissions and proper biochar production. Strict methodology-level requirements are not set because: * Thermocouple setups (number, placement, spacing) vary by kiln design. * Different biomass feedstocks produce distinct temperature curves due to varied energy content. * Universal temperature thresholds are not yet established. Ideally temperature sensors will be used to prove that pyrolysis remains **above 500-550°C**, which is a more robust sign of high-quality pyrolysis than 350°C. However, due to the novelty and expected difficulties in this technology's early deployment, this requirement remains flexible for the time being. {% endhint %} ### Trainings Upon validation, Project Developers shall submit their Training Protocol, describing how they ensure: * frequency of trainings for Kiln Operators and Kiln Supervisors * testing or proof of adequate completion of training * ongoing training and support #### Kiln Operator training Project Developers are responsible for ensuring regular trainings are provided to Kiln Operators involved in their project. The Kiln Supervisor or the Project Developer may be the party providing training. Training shall cover at least the following aspects of kiln operation: * safety provisions for operating the kiln * biomass preparation (drying, eligible biomass size, appropriate size of biomass) * taking biomass moisture content measurements * feeding biomass into the kiln to ensure consistent pyrolysis * rapid quenching * managing the [biochar sampling procedure](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements.md#biochar-sampling-procedure) * use of dMRV #### Kiln Supervisor training Project Developers shall justify the expertise and qualifications of Kiln Supervisors. This may be through dedicated training or previous relevant experience. This shall cover at a minimum: * all points listed above, to be transmitted to Kiln Operators * biochar amount measurements, including bulk density and moisture content [^1]: - Rodrigues, L., Budai, A., Elsgaard, L., Hardy, B., Keel, S.G., Mondini, C., Plaza, C., Leifeld, J., 2023. The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice. European Journal of Soil Science 74, e13396. [https://doi.org/10.1111/ejss.1339](https://doi.org/10.1111/ejss.13396) - Rudra, A., Petersen, H.I., Sanei, H., 2024. Molecular characterization of biochar and the relation to carbon permanence. International Journal of Coal Geology 291, 104565. - Wang, J., Xiong, Z., Kuzyakov, Y., 2016. Biochar stability in soil: meta-analysis of decomposition and priming effects. GCB Bioenergy 8, 512–523. - Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409. [^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.
A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first. [^3]: Inertinite is a type of maceral. Macerals are the organic compounds in materials like coal and shale, and are extremely permanent. They are analogous to mineral carbon in rocks. [^4]: * Schmidt, H.-P., Kammann, C., Hagemann, N., Leifeld, J., Bucheli, T.D., Sánchez Monedero, M.A., Cayuela, M.L., 2021. Biochar in agriculture – A systematic review of 26 global meta-analyses. GCB Bioenergy 13, 1708–1730.[ https://doi.org/10.1111/gcbb.12889](https://doi.org/10.1111/gcbb.12889) * Joseph, S., Cowie, A.L., Van Zwieten, L., Bolan, N., Budai, A., Buss, W., Cayuela, M.L., Graber, E.R., Ippolito, J.A., Kuzyakov, Y., Luo, Y., Ok, Y.S., Palansooriya, K.N., Shepherd, J., Stephens, S., Weng, Z. (Han), Lehmann, J., 2021. How biochar works, and when it doesn’t: A review of mechanisms controlling soil and plant responses to biochar. GCB Bioenergy 13, 1731–1764.[ https://doi.org/10.1111/gcbb.12885](https://doi.org/10.1111/gcbb.12885) [^5]: Carbon dioxide removal [^6]: WBC (2023): World Biochar Certificate – Guidelines for a Sustainable Production of Biochar and its Certification.' Carbon Standards International, Frick, Switzerland, (), version 1.1 from 20th December 2024. [URL](https://www.carbon-standards.com/en/standards/service-514~production-of-biochar.html). [^7]: Indigenous peoples are defined in the [Glossary](https://docs.rainbowstandard.io/glossary#general) as people that self-identify as Indigenous and are recognized by others as Indigenous, with historical continuity with pre-colonial societies; distinct languages, customs, and institutions; a strong connection to ancestral lands or territories; and are often governed by customary laws or traditional authorities. Local communities are defined in the [Glossary](https://docs.rainbowstandard.io/~/changes/180/glossary#general) as non-Indigenous people with a long-standing connection to a particular rural or semi-rural geographic area; reliance on local natural resources for livelihood; social cohesion or shared cultural traits, though not necessarily Indigenous; living in geographic proximity to a part of the project area, including but not limited to sourcing, production, and/or end use locations. [^8]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.
A production batch is valid for a maximum of 6 months operating time or 100 tonnes of biochar, whichever comes first. [^9]: digital monitoring, reporting and verification [^10]: There is no specific format or template to follow. Exported data must be in a widely usable and accessible format and file type, to ensure that data remain accessible outside of the dMRV platform. [^11]: Amount of biochar produced **does not need to match exactly** the amount reported as applied within the same monitoring period, as biochar may be stored and applied in a later monitoring period. Cumulative biochar production records must remain consistent with cumulative end-use application records across monitoring periods --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.rainbowstandard.io/methodologies/distributed-closed-kiln-biochar/principles-and-requirements.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.